1. Field of the Invention
The present invention relates to a system for warning against forgetting to pull out an information recording medium (hereinafter also referred to simply as a “forget-to-pullout information recording medium warning system”) that serves to prevent a user from forgetting to pull out an information recording medium from an on-board radio unit in case where a drive unit of a vehicle is stopped with the information recording medium remaining in the on-board radio unit.
2. Description of the Related Art
ETC (Electronic Toll Collection) systems are becoming increasingly prevalent, and the number of vehicles with on-board devices in the form of on-board radio units installed thereon is increasing in recent years.
In order to use ETC systems, it is necessary for a user to insert an ETC card in the form of an IC card into an on-board device installed on a vehicle, whilst when leaving the vehicle, the user needs to pull out the ETC card from the on-board device for the purpose of anti-theft.
In addition, although not only ETC but also a variety of other services using on-board devices and IC cards are being studied now and in the future, it is undesirable, in any of these services, to leave an IC card in a vehicle because of fear such as theft of the card.
Accordingly, for example, as a forget-to-pullout card warning system, there has been known one in which when it is detected that a card exists in an on-board device installed on a vehicle and a drive unit of the vehicle is in a stopped state, an alarm is provided to a user so as to draw attention by using a notification part such as a buzzer, a voice system, etc., mounted on the on-board device (see, for example, a first patent document (Japanese patent application laid-open No. H11-39438)).
In such a forget-to-pullout card warning system as stated above, however, in order to achieve the above function, it is necessary to detect the state of remaining of the card (i.e., the state of the card remaining in the on-board device) after the drive unit of the vehicle is stopped, i.e., after a power supply is turned off. Thus, the on-board device must be connected to not only a power supply line to which a drive unit switch of the vehicle is connected, but also an on-board battery backup power supply line which is connected to an on-board battery so as to be always supplied with electric power. As a result, there is a problem of poor workability when the on-board device is installed on the vehicle.
Moreover, in case where a navigation unit is installed on the vehicle, it is necessary to connect the power supply line and the backup power supply line to the navigation unit, similar to the on-board device, thus posing another problem that the working efficiency is remarkably deteriorated.
Further, although the number of vehicles with navigation units installed thereon is increasing in recent years, there is also a further problem as stated below. That is, an alarm as referred to above is issued by the on-board device itself, so there is generally a great difference in tone quality between a voice guidance from the navigation unit and that issued by the on-board device during operation of the drive unit of the vehicle, and hence users feel an uncomfortable sensation and are not able to obtain a sufficient degree of satisfaction.
Furthermore, in order to make an IC card remaining in the interior of an on-board device difficult to see from outside of a vehicle, many users generally arrange the main body of the on-board device in a place difficult to see from outside of the vehicle, such as in the vicinity of the feet of a driver, a glove box or the like. In this case, however, there is a still further problem, too, that even if the on-board device issues a warning of forgetting to pull out a card therefrom, the users can not easily hear the warning because of the arrangement of the on-board device in such a place.
Additionally, providing a notification function for each of the navigation unit and the on-board device will impose a double investment on users, so there is a problem of accordingly increased cost, too.